I buy a lot of my food as bulk staples.
I am not sure why people don't prepare more of their own food, but I suspect that they have been sold the idea that it is more work than it really is.
I even see people in my family buying pancake mix.
All that goes into pancake mix is flour, baking powder and a little bit of sugar. If you want egg or milk you have to add it yourself.

My aunt used to hate the idea of cooking rice because she would stand there at the stove simmering and stirring it, and then it would come out as gooey sticky mush.
She started serving rice far more often once she saw how you could just put the rice and water in a pot, bring it to a boil, and set it off the stove to finish cooking. (backpacker trick)
Especially when she found it came out light and fluffy that way.
She was impressed enough with the no fuss way of cooking rice that when my uncle bought her a rice cooker she sent it back because it took too much effort and too much counter space.
She cooks oatmeal like that now too.

Anyhow, what you are describing isn't just UK/EU.
It seems to be all through Canada and USA too.

I admit to buying too much bakery bread myself, but that is because we don't like heating up the house with the oven in the summer.